Sinistrorsely twining herbs with white milky juice. Leaves spirally arranged, simple or lobed to varying degrees, cordate, palmatinerved, long-petioled, glabrous as is the stem, exstipulate. Flowers bisexual, or polygamous (andromonoecious), small, subsessile, in unilateral repeatedly forked cincinni, composed of loose axillary panicles, ebracteate. Calyx deeply (4-)5-partite, lobes imbricate in bud, whether or not slightly accrescent in fruit, persistent. Petals (4—)5, caducous, lower half forming a widely funnel-shaped corolla, lobes imbricate in bud. Stamens (4-)5 inserted on the upper part of the corolla tube, alternate with its lobes; filaments very short, glabrous; anthers medifixed, introrse; pollen grains oblate, triangular in polar view, tricolporate. Disk absent. Ovary oblong-ovoid, subquadrangular (rudimentary in ♂), 1-celled; styles 2, one with a deep longitudinal groove, and two inequal ovate rather obtuse distal divisions, accrescent in fruit and becoming linear and succulent then, the other short-curved, capitate at apex, deciduous; ovules 2 (often one of them aborted), pendent from apex of cavity, anatropous, with dorsal raphe. Fruit indehiscent, compressed, with 2 longitudinal broad and transversely striate stramineous wings, obovate-elliptic to orbicular in outline, apex emarginate, crowned by the columnar accrescent soft and green stigma, base very shortly or hardly (Mai.), sometimes elongately contracted into a kind of stipe. Seed 1, linear, sulcate; testa thin; embryo minute, conical, in top of granular fleshy albumen. Distr. Two spp., one in SE. Asia and W. Malesia, and one in E. Malesia.